The instant invention relates to the art of lateral translation of a supply or take-up roll of a continuous web of material to maintain the roll in proper alignment as the material is paid from the roll for some form of treatment or rewound onto the roll to be paid from the roll again in an aligned manner for further treatment of the web.
The invention has application to electrographic recording systems for forming electrostatic latent images on a continuous web of material comprising a recording medium and is particularly applicable to the color electrographic art and electrographic apparatus for consecutively forming a plurality of latent component images on a recording medium from a supply roll to a take-up roll in the apparatus, which component images are sequentially developed with a respective color developer or toner and which images must be superimposed to produce a composite color image on the recording medium.
Commercially successful electrographic apparatus in the past has involved one recording station and one development station with one toning medium, which is usually black. In recent years there has been increasing pressure on electrographic system vendors to create and develop reliable color electrographic systems. This is particularly true because of the increased application of color CAD/CAM system usage and color LSI/VLSI design mandating the use of color display and design and, consequently, requiring color hardcopy output.
Going from single color to multiple color electrographic recording, a complex problem is encountered. In single color recording, the latent image is formed followed by its immediate development. However, in color recording, two or more latent images must be independently formed and developed and superimposed upon one another. Thus, some means of registration is mandatory to insure that the different color component images are sufficiently superimposed to prevent color fringes and color errors and provide a high resolution color print useful in the above-mentioned applications. Part of such a registration means would be to correct for inconsistency of the length of the core in which the medium is rolled. This inconsistency is compensated for by lateral adjustment of the supply roll and/or take-up roll for the recording medium to insure that the medium is properly aligned for treatment as it is paid from the roll. The other part of such registration means is the weave pattern of the medium length which is compensated by electrographic head adjustment which is the subject of the previously identified patent application Ser. No. 444,144.